Air Powered Motor

As a kid I had a an air powered toy car. Yesterday I got the idea to try and design an air powered motor which can later be incorporated in all kinds of applications.

I'm not going to explain the principle as the animated GIF in this link explains it perfectly:

http://www.animatedengines.com/co2.shtml

As I have only completed my design work today I haven't yet had a chance to print it and look for any flaws. Also for the sake of easily printing all the parts the design might be slightly